The present invention relates to a semiconductor device, a position detection device, and a control method of a semiconductor device. For example, the present invention can be preferably applied to a semiconductor device that samples a signal.
A position detection device and a position indicator (typically, a pen) of an electro magnetic resonance (EMR) method are known (for example, Japanese Patent No. 2971488, Japanese Patent No. 2583500, Japanese Unexamined Patent Application Publication No. 2003-067124, and Japanese Patent No. 2635082).
According to Japanese Patent No. 2971488, the position detection device transmits and receives a signal by electro magnetic resonance between one loop coil selected from a plurality of loop coils and a pen and calculates amplitude and phase of a reception signal received from the pen. The position detection device repeats the same operation as described above by sequentially selecting the plurality of loop coils. Then, the position detection device detects the position of the pen based on amplitude and phase of a reception signal in each loop coil.
According to Japanese Patent No. 2583500, the position detection device repeats switching of transmission and reception between one loop coil and the pen seven times and averages (integrates) induction voltages (reception signals) generated in seven reception periods. The reason to perform the averaging is to alleviate effects of external noise according to Japanese Unexamined Patent Application Publication No. 2003-067124.